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Seriously attempt a keyboard controller.

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This commit is contained in:
Thomas Harte 2023-11-23 22:10:51 -05:00
parent 0674da0325
commit 44d602e0f6
1 changed files with 74 additions and 19 deletions
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93
Machines/PCCompatible/PCCompatible.cpp
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@ -35,6 +35,69 @@
namespace PCCompatible {
class KeyboardController {
public:
KeyboardController(PIC &pic) : pic_(pic) {}
// KB Status Port 61h high bits:
//; 01 - normal operation. wait for keypress, when one comes in,
//; force data line low (forcing keyboard to buffer additional
//; keypresses) and raise IRQ1 high
//; 11 - stop forcing data line low. lower IRQ1 and don't raise it again.
//; drop all incoming keypresses on the floor.
//; 10 - lower IRQ1 and force clock line low, resetting keyboard
//; 00 - force clock line low, resetting keyboard, but on a 01->00 transition,
//; IRQ1 would remain high
void set_mode(uint8_t mode) {
mode_ = Mode(mode);
switch(mode_) {
case Mode::NormalOperation: break;
case Mode::NoIRQsIgnoreInput:
pic_.apply_edge<1>(false);
break;
case Mode::ClearIRQReset:
pic_.apply_edge<1>(false);
[[fallthrough]];
case Mode::Reset:
reset_delay_ = 5; // Arbitrarily.
break;
}
}
void run_for(Cycles cycles) {
if(reset_delay_ < 0) {
return;
}
reset_delay_ -= cycles.as<int>();
if(reset_delay_ < 0) {
post(0xaa);
}
}
uint8_t read() {
pic_.apply_edge<1>(false);
return input_;
}
private:
void post(uint8_t value) {
input_ = value;
pic_.apply_edge<1>(true);
}
enum class Mode {
NormalOperation = 0b01,
NoIRQsIgnoreInput = 0b11,
ClearIRQReset = 0b10,
Reset = 0b00,
} mode_;
uint8_t input_ = 0;
PIC &pic_;
int reset_delay_ = 0;
};
class MDA {
public:
MDA() : crtc_(Motorola::CRTC::Personality::HD6845S, outputter_) {}
@ -276,7 +339,7 @@ using PIT = i8237<false, PITObserver>;
class i8255PortHandler : public Intel::i8255::PortHandler {
// Likely to be helpful: https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-XT-Keyboard-Protocol
public:
i8255PortHandler(PCSpeaker &speaker) : speaker_(speaker) {}
i8255PortHandler(PCSpeaker &speaker, KeyboardController &keyboard) : speaker_(speaker), keyboard_(keyboard) {}
void set_value(int port, uint8_t value) {
switch(port) {
@ -289,6 +352,8 @@ class i8255PortHandler : public Intel::i8255::PortHandler {
// b2: [5150] high or low switches select; [5160] 1 => disable turbo mode;
// b1, b0: speaker control.
enable_keyboard_ = !(value & 0x80);
keyboard_.set_mode(value >> 6);
high_switches_ = value & 0x08;
speaker_.set_control(value & 0x01, value & 0x02);
break;
@ -296,21 +361,12 @@ class i8255PortHandler : public Intel::i8255::PortHandler {
printf("PPI: %02x to %d\n", value, port);
}
// KB Status Port 61h high bits:
//; 01 - normal operation. wait for keypress, when one comes in,
//; force data line low (forcing keyboard to buffer additional
//; keypresses) and raise IRQ1 high
//; 11 - stop forcing data line low. lower IRQ1 and don't raise it again.
//; drop all incoming keypresses on the floor.
//; 10 - lower IRQ1 and force clock line low, resetting keyboard
//; 00 - force clock line low, resetting keyboard, but on a 01->00 transition,
//; IRQ1 would remain high
uint8_t get_value(int port) {
switch(port) {
case 0:
printf("PPI: from keyboard\n");
return enable_keyboard_ ? keyboard_ : 0x00; // ?
return enable_keyboard_ ? keyboard_.read() : 0b0011'1100;
// Guesses that switches is high and low combined as below.
case 2:
// Common:
@ -336,14 +392,9 @@ class i8255PortHandler : public Intel::i8255::PortHandler {
private:
bool high_switches_ = false;
PCSpeaker &speaker_;
KeyboardController &keyboard_;
bool enable_keyboard_ = false;
uint8_t keyboard_ = 0x00;//0xaa;
// Provisionally, possibly:
//
// port 0 = keyboard data output buffer;
//
};
using PPI = Intel::i8255::i8255<i8255PortHandler>;
@ -800,8 +851,9 @@ class ConcreteMachine:
[[maybe_unused]] const Analyser::Static::Target &target,
const ROMMachine::ROMFetcher &rom_fetcher
) :
keyboard_(pic_),
pit_observer_(pic_, speaker_),
ppi_handler_(speaker_),
ppi_handler_(speaker_, keyboard_),
pit_(pit_observer_),
ppi_(ppi_handler_),
context(pit_, dma_, ppi_, pic_, mda_)
@ -867,6 +919,8 @@ class ConcreteMachine:
// i.e. CPU instruction rate is 1/3 * ~1.19Mhz ~= 0.4 MIPS.
//
keyboard_.run_for(Cycles(1));
// Query for interrupts and apply if pending.
if(pic_.pending() && context.flags.flag<InstructionSet::x86::Flag::Interrupt>()) {
// Regress the IP if a REP is in-progress so as to resume it later.
@ -945,6 +999,7 @@ class ConcreteMachine:
PCSpeaker speaker_;
MDA mda_;
KeyboardController keyboard_;
PITObserver pit_observer_;
i8255PortHandler ppi_handler_;